The kinds of flat panel display (FPD) includes field emission display (FED), liquid crystal display (LCD), plasma display panel (PDP), organic light emitter device (OLED), and liquid crystal projection display . . . etc. The common features of such display are thin and light weight. According to the property of every flat panel display, some of them can be applied on the small scale panel such as cellular phone, a little part of them being suitable to be applied on the medium or large scale device such as computer monitor or TV display, another application for them further comprising super large scale display device such as the outdoor digital exhibition board. But the technology of every kinds of the flat panel display all progress toward the object of high display quality together with large scale display and raising the duration life for application.
A new technology of carbon nanotube field emission display (CNT-FED) has the opportunity to have all the progressive property of the above-mentioned features. Please refer to the FIG. 1, the mentioned carbon nanotube field emission display is manufactured by the principle of field emission. Wherein the operation method is to apply the electrical field to induce the electrons from the tip of the electrical source 104 of the carbon nanotube. Applying the vacuum environment, the field emitting electrons can be pushed and forced by the positive voltage from the top base glass plate 100 having phosphors powder 102. Thus the electrons can accumulate its energy to strike the relative phosphors powder 102 to generate the light.
Thus from the above mentioned field emission display, the mentioned vacuum environment is established by the packaged of the cathode plate 122 and the anode plate 120 to draw out the air to form a vacuum region or a so-called package region 112. The vacuum degree in the vacuum sealing region is at least from 10−6 Torr to cause the residual air not interfering the field emission electrode. The vacuum degree should prevent the plasma generation to reduce the efficiency of light radiation and the reducing of duration life of the carbon nano tube.
Regarding the conventional art, for reaching the purpose of vacuum package, a kind of special glass glue with chemical bonding ability in high temperature is needed. The two process of high temperature treatment is required. The first treatment is called the pre-heating and by the temperature of 350 to 400 centigrade to oxidize the organic solvent in the glass glue. The second treatment is called fritting and by the temperature of 440 to 480 centigrade to cause the chemical bond for forming the larger molecules to ensure the sealing property and the connection strength. Thus the said glass material for chemical bond in the high temperature should have the property of certain bonding strength, no residue of volatile gas, low generation of dust. But during the heating process, the many internal material inside the cathode plate and the anode plate such as the electrical source 104 of the carbon nanotube, gas seal material and phosphors powder 102 should sustain two times of the process of high temperature. The high temperature may usually cause an effect to the property and quality of internal material. So the inventor think the problem how to reduce the times of high temperature treatment to the cathode plate and the anode plate to reduce the uncertainty factor to the property and quality of internal material.
The FIG. 1 shows the structure of the first prior art for a field emission display. It is generally to be divided into the cathode plate 122, the anode plate 120, vacuum sealing region 109 and the phosphors powder 102 deposited on the top base glass plate 100. The called anode plate 120 includes the phosphors powder 102 and the top base glass plate 100. The electrical source 104 of the carbon nanotube is deposited on the bottom base glass plate 110 to be used as electrical emitting source. The called cathode plate 122 includes the electrical source 104 of the carbon nanotube and the bottom base glass plate 110. The described prior art is requiring to apply the glass side strip 106 to keep a certain distance between the bottom base glass plate 110 and the top base glass plate 100 by the certain value of 0.5 mm to 2 mm. The alignment mark of the glass side strip 106 is marked by the photolithographic image or the laser process to decide the location of the glass side strip 106 on the bottom base glass plate 110 and the top base glass plate 100.
In the process of package, first step is to spread the glass glue 108 on the alignment marked location of top base glass plate 100 for the glass side strip 106, then the operator places the glass side strip 106 on the alignment marked location. Through the first pre-heating to fix the glass side strip 106 on the top base glass plate 100, the operator should spread the glass glue 108 on another surface of the fixed glass side strip 106 to proceed to one more pre-heating process to oxidize the organic solvent in the glass glue 108. The following step is to proceed to the temporary fixing by a kind of certain UV glue for the bonding of the bottom base glass plate 110 and the top base glass plate 100 through alignment. The purpose of the said temporary fixing is to keep the precision to prevent the distortion. The general application for temporary fixing is applied by the UV glue.
After the temporary fixing, the operator applies a kind of the fixing tool to fix the cathode plate 122 and the anode plate 120, proceeding to high temperature heat treatment as fritting. Thus the connection of the glass side strip 106 between the bottom base glass plate 110 and the top base glass plate 100 will be formed. But the UV glue will be decomposed in the high temperature treatment to pollute the glass glue. So the location of UV glue for the temporary fixing will be arranged as far as possible from the location of glass glue.
After the package of the bottom base glass plate 110 and the top base glass plate 100, the operator will proceed the vacuum pumping and sealing. Since the operation environment of the field emission display require the vacuum degree of 10−6 Torr, the operator will apply a kind of gas getter material as chemical pump to increase the efficiency of gas pumping and to catch the escaping air, the life of vacuum being extended by the said gas getter material. Sum up the prior art, though the art can reach the vacuum package, the remained problems is occurred such as hard control to distortion by the fixing tool at the period of heat treatment. This distortion is very hard to control between the cathode plate 122 and the anode plate 120.
Further, please refer to the other prior art as described in the FIG. 2 and FIG. 3. for the method of package. By using the photolithographic image or the laser process, the alignment mark can be added on the bottom base glass plate 110 and the top base glass plate 100. Then the respective heat treatment by high temperature will be applied by using the U shape glass side strip 206 fixed on the predetermined location of top base glass plate 100 and by using the U shape glass side strip 204 fixed on the predetermined location of bottom base glass plate 110. Then according to the alignment mark on the bottom base glass plate 110 and the top base glass plate 100, the operator can catch the precise alignment to proceed to temporary fixing. In addition, the groove 212 between the two U shape glass side strips 204,206 will be filled with the glass glue. This method of prior art can improve the distortion occurred in the conventional fixing method. The said distortion is caused by the nonuniform spreading of glass glue between the glass side strip 206 and the anode plate 120 to cause the displacement between the cathode plate 122 and the anode plate 120 to affect the alignment precision. This art can improve the distortion problem after the fritting of the cathode plate 122 and the anode plate 120. But the art still have some problems in need of solution.
1. The operation bottleneck is high.
(1) The fixing area of UV glue for temporary fixing is reduced.
The cathode plate 122 and the anode plate 120 should be applied temporary fixing after alignment. But the groove 212 between the two U shape glass side strip 204, 206 is for filling the glass glue. Thus the packing area and the sealing area for glass side strip 204, 206 are enlarged. This is just opposite to the requirement of common product that the effective area and picture area should be large and the void area and non-picture area should be small. This condition is also lead to the fixing area of UV glue for temporary fixing hard to be executed by lacking of void area.
(2) The times of alignment for package is increased together with the complexity of process being increased.
Since the U shape glass side strips 204,206 should be aligned and fixed on the cathode plate 122 and the anode plate 120 respectively, the cathode plate 122 and the anode plate 120 proceeding to align and to temporarily fix, the groove 212 between the two U shape glass side strips 204,206 being necessarily kept in a uniform distance, consequently the complexity and the hardness are increased.
(3) The process of glue spreading is more complex
The dimension of the two U shape glass side strips 204,206 are different. So the process of glue spreading are executed respectively. The additional process to spread glue in the groove 212 between the U shape glass side strips 204,206 is the third glue spreading process. Thus the complexity of process and the equipment cost are raised.
2. The times for the cathode plate 122 and the anode plate 120 to enter into the heat treatment device are increased
Since the organic solvent of the glass glue should be oxidized, the pre-heating process is necessary after the spreading of the glass glue. But many kinds of material will be coated on the cathode plate 122, the anode plate 120 and the gas getter fixing region. These kinds of material have limited restriction to the high temperature process. Thus the more times of high temperature treatment will cause more restrictions to the selection of the coated material on the cathode plate 122 and the anode plate 120. The art described here will cause a more pre-heating and more fritting region. The risk of the manufacturing process is increased.
For the above mentioned, the inventor design a self-adhesive frame applied in package of field emission display to resolve the above mentioned problems. Please refer to the below description.
1. Raise the operation convenience
(1). The present invention can provide a fixing side strip 402 for the UV glue to establish the temporary fixing. Further function can be shown in the fritting in high temperature by the reason of enough interfering distance between the UV glue and the glass glue 108. So the UV glue will not pollute the glass glue at the decomposition period to prevent the leakage of inner vacuum environment.
(2). The present invention can provide the function of reducing the accuracy requirement or complexity of the alignment.
(3). The present invention can apply the independent manufacturing. After the manufacturing process, the operator can introduce the independent component into the alignment process of the cathode plate 122 and the anode plate 120. Thus the glue spreading process can be reduced.
2. Reducing the times of heat treatment in high temperature for the cathode plate 122 and the anode 120.
The present invention can apply the temporary fixing to the cathode plate 122, the anode plate 120, and the gas getter to attach to a predetermined location from alignment. Thus the one time for heat treatment of fritting with pressing fixing is executed.
3. The distortion after the temporary fixing can be improved
The prior art easily generates the problem of nonuniform spreading of the high temperature glue. This condition will cause a displacement action between the cathode plate 122 and the anode plate 120. Thus, the glass glue will generate a slipping condition during the high temperature heat treatment. Whereas, the present invention has a high uniformity at the package surface that can overcome the problem of nonuniform high spreading of the high temperature glue.